MSPs will vote on a Labour call for Scotland's railway services to be taken back into public ownership at the earliest opportunity.

The party argues rail privatisation has "failed" and it has forced a vote on the future of the ScotRail franchise at the Scottish Parliament on Wednesday.

Scottish Labour is urging ministers to exercise an early "break clause" in the deal with current operator Abellio, which it says would bring the franchise to an end in around four years' time.

It comes after figures released last month put ScotRail's performance level at its lowest since the franchise began.

Scottish Labour's transport spokesman Colin Smyth said: "MSPs today can hit the brakes on failed rail privatisation by backing Labour's bid to exercise the break clause in the ScotRail contract.

"Abellio was supposed to be a world-leading contract for ScotRail. Instead passengers are suffering from overpriced, overcrowded trains that are frequently cancelled or skipping stops.

"The SNP promised to work up a public-sector bid for the railways - if that was a serious promise they should be willing to exercise the break clause so that operator can step in."

Dutch operator Abellio began a ten-year contract to run the franchise in 2015.

Labour maintains that under the terms of that agreement, the Scottish Government can exercise an opportunity in 2020 to end the franchise by its first expiry date in 2022.

The party said it will argue the case for public ownership of the railway.

The Labour motion to be debated in the Holyrood chamber is: "That the Parliament believes that the Scottish Government should exercise the break clause in the ScotRail franchise at the earliest opportunity."

A Scottish Government spokeswoman said: "We know performance is not where it should be - that is why ministers can and do hold Abellio ScotRail to account within the terms of the franchise agreement.

"This includes the ability to end the contract if its terms are not met and it is in the public interest to do so - nothing has changed in this regard."

A spokesman for Abellio claimed infrastructure challenges - the responsibility of publicly owned Network Rail - were the primary cause of negative train performance.

He added: "Whilst challenges remain, Abellio is investing £475m in new electric and high-speed trains, which will significantly improve customer experience and connectivity.

"We believe in a partnership approach - bringing together the private and public sector - to deliver a step change in passenger services."